Aldonyl anesthetic compounds and their salts



Patented Mar. 25, 1941 UNITED STATES ALDONYL ANESTHETIG'COBIPOUNDS' AND THEIR SALTS;

David Curtis, New York, N. Y.

N Drawing. Application February16,1937 Serial No. 125,980-

14 Claims. (Cl'. 260-471) The present invention relates to compounds of esters of amino-aromatic acids with the lactones of aldonic'acids, and is a continuation-impart application of my copending application entitled Aldonic acid salts of anesthetics, filed April '7,

1936, Serial No. 73,137.

It is the object of the present invention to provide a new group of anesthetic compounds by linking esters of amino-aromatic acids, such as the esters of cinnamic, hydrocinnamic and benzoic acids, and the like, with the lactones of aldonic acids of the pentoses, hexoses and heptoses varieties, such as the lactones of gluconic acid, galactonic acid, mannonic acid, arabonic acid, xylonic acid, a-glucoheptonic acid, and the like, to form aldonyl-amino-aromatic acid esters.

It is a further object of the present invention to provide salts of the aldonyl-amino-aromatic acid esters of the character. described with various acids, acid salts and acid substances, both of the organic and inorganic types, such as sulphuric, hydrochloric, boric, picric, cinnamic, acetyl-salicylic, benzoic, toluic, tartaric, citric and malic acids, and the like, and potassium hydrogen sulphate and the like.

The aldonyl-amino compounds of the present invention have among their characteristics an increased anesthetic potency and an increased solubility in water, to the extent that the aldonyl compounds of otherwise insoluble anesthetic bases become appreciably soluble in water, so that their aqueous solutions produce an appreciable anesthetic effect when applied to mucous tissue. These characteristics of greater anesthetic potency and increased solubility in water of the aldonyl compounds of the present invention are also possessed by their salts.

A further advantageous characteristic of the aldonyl compounds of the present invention and their salts is that the aldonic lactone grouping present is a natural food element of the body and is, therefore, compatible with the body tissues and easily assimilable therein, and is, consequently, completely non-toxic.

As representative of the esters of amino-aromatic acids which may form aldonyl compounds we may take the alkyl, aryl, alkamine and alcohoh alkamine esters of amino benzoic acid, such as diethyl amino ethanol-p-amino-benzoate (pro-. cain). ethyl-p-amlno-benzoate (benzocaine) propyl-p-amino-benzoate (propesin) ,butyl-p-aminobenzoate (butesin), gamma-di-normal butylamino propanol p. amino benzoate (butyn) methyl -meta amino p oxy benzoate (orthoform), benzyl-p-amino-benzoate, ethyl-p-aminocinnamate, and the like. And as representative of the aldonic acid lactones with-which the above may be linked to form their aldonyl compounds We may take the lactones of gluconic and galactonic acids. The linkage between the two substances, the anesthetic base and the aldonic acid lactone, takes place by the displacement of one or both available hydrogens of the amino grouping of the aromatic radicle by one or two, as the case may be, aldonic acid lactones, which then assume the aldonyl arrangement by incorporating the displaced hydrogen into their structure. The resultant compounds may be represented by the following structural formulae, the first formula representing a mono-aldonyl amino compound and the second formula 2. di-aldonylamino compound:

Formula 1 o o 0 R RNH Formula 2 c o o R wherein R stands for the alcoholic grouping of the. esters, which. may constitute either an aryl, an alkyl, an alkamin or an alcohol-alkamin radicle, and, R stands for an aldonyl grouping. The general methods for preparing any of the above aldonyl compounds include the following:

Aweighed quantity of an anesthetic base is dissolved in a volatile solvent, such as dioxane. A substantially equimolecular quantity of the aldonic acid lactone is dissolved in water, preferably in an amount of water substantially equal in Weight to the weight of the lactone. The two solutions are then brought together and subjected to heat treatment under pressure, preferably a pressure of about 22-25 pounds, until the reaction is complete. The time of the application of the pressure, depends on the quantities used. When the reaction is complete, as far as it will go, the pressure is removed and the solvents driven off, first by heat and then finishing under reduced pressure, or completely under reduced pressure. The anesthetic aldonyl compound formed is then treated for purification, the treatment varying in accordance with the individual characteristics of the various aldonyl anesthetic compounds. Thus, a preferred method for the purification of the aldonyl compounds that are not soluble in cold water is from hot water, in which they are all soluble. The water soluble aldonyl compounds may be purified by crystallization from a volatile vehicle, alcohol, for instance.

Another method, that may be used to prepare the aldonyl compounds of the present invention. is to melt a Weighed quantity of the aldonic acid lactone over a low flame and then to stir into the molten lactone a substantially equimolecular.

quantity of the desired anesthetic ester, continuing to stir the molten mass for some time.

A small amount of a volatile solvent, such as alco- (Procaine-aldonyl comp.)

hol may then be added to the molten mass and amount of alcohol not appreciably affecting the solubility of the benzocaine aldonylin the water after it is cooled.

As specific examples of the aldonyl-anesthetic compounds of the present invention we may take the following:

Example 1 Procaine gluconyl compound,-diethyl-aminoethanol-p-gluconyl-amino-benzoate. The above compound has the structural formula of It may be prepared by dissolvin 17.8 gramsof delta-glucono-lactone in about 20 cc. of water and by dissolving 23.6 grams of procaine base in about 100 cc. of acetone, bringing the solutions together and subjecting the mixture to steam pressure of about 20lbs., until the reaction is 3 complete. The solvents are then driven off under low heat and reduced pressure. The reaction taking place may be representedas follows:

COO.C2H4N 02H 5 Hc-oH\ I O --0 HOC .NH:

(Procaine) (d-Glucono-la ctone) The resulting compound is an amber colored tacky substance, balsamic in appearance. It is soluble in water giving an alkaline reaction to litmus and has a pH of 7.5 to 7.7 brom thymol blue.

' .Example 2 Procaine galactonyl compound,-diethyl-aminoethanol-p-galactonyl-amino-benzoate. It may be similarly'p'repared from similar proportions of the reactants. The resulting compound probably has the general structural formula of C O 0.02HiN It-is also an amber colored, tacky, balsamic substance, soluble in water and alcohol, its solution in water being alkaline to litmus and giving in a 2% solution a pH of about 7.5 brom thymol blue.

Example 3 Bentocairie glucon yl compound,-ethyl-p-gluconyl-amino-benzoate. This compound may be prepared by dissolving 71.2 grams of delta-glucono-lactone in about '70 cc. of water, preferably by the application of heat, and separately dissolving 66.0 grams of benzocaine base in about 200 cc. of dioxane or acetone, bringing the solutions together and subjecting the mixture to steam pressure of about 22 lbs. for about an hour. Whenthe reaction is completed as far as it will go, the bulk of the solvents is removed by low heat under reduced pressure.

The remaining material is then' treated with boiling water in which the'benzocaine gluconyl compound is soluble, and the insoluble matter filtered ofi. The filtrate is then thoroughly cooled and the crystals of benzocaine gluconyl compound thus precipitated. are filtered off and dried under reduced pressure, to. drive off the remaining water. The resulting. product is a White crystalline substance, substantially soluble in hot Water, hydrolizing therein. Itis sparingly soluble in cold water,

giving a substantially'stable solution of appreciable anesthetic value which has a slightly acid reaction. The probable structural formula of the compound is o o 0.0m,

nN-e

rat-H noi H Ham;

Example 4 Benzocainegalactonyl compound,-ethyl-p.- galactonyl-amino-benzoate. This compound may be prepared in. the same manner as the benzecaine gluconyl compound, using, if desired, the gamma-galactono-lactone, which. contains one molecule. of water of crystallization. It is also a white, crystalline substance, sparingly soluble in cold water, giving a slightly acid. reaction. Its structural. formula. may also. be written as deltaiorms of the lactones. of. the. various aldonicv acids give the same end products when used; however, when. the gamma form of the lactones is used, itv may be necessary to use a slight excess of the lactone to promote. a more ready reaction.

Other amino aldonyl. compounds that. I have prepared include propyl-p-galactonyl-aminobenzoate, butyl-p-gluconyl amino-benzoate and butyl-p-galactonyl-amino-benzoate.

When any of the. aldonyl-anesthetic compounds of the present'invention combine with acids or acid substancesv to form salts, they form substances. having the general structural formula of where R stands for an alkyl, aryl oralkamine radicle, R for. the aldonyl grouping and X for the acid'o-r acid substance. As'spe'cific examples of such acid salts we maytakethefollowing:

Ethyl p-gluconyi-amino benzoate potassium hydrogen sulphate. It may be prepared by add ing 33.5 grams of the benzocaine gluconyl compound to a solution of 13-.2 grams of potassium hydrogen sulphate (KHSOO- in 200 cc, of boiling water. The mixture is then heated until the reaction is completed. It is then thoroughly cooled to allow the acid salt formed to precipitate out in white glistening needle-like crystals. The crystals are then filtered off and dried. The

In the suggestedfformula it may be considered that the amino grouping. of the anesthetic base (NI-I2) is the equivalent of an ammonium radicle (NH3) in which one of the hydrogens has been replaced by the ethyl-benzoyl grouping, and the other hydrogen has been replaced by the aldonyl grouping. Thus in analogy to ammonium chloride, NH4C1, which may be written as the. abovev acid compound may also be written as follows:

ominous-.11..

-H.rn:so.

C-O.(HC OH) 4.011 011 (Aldonyl).

Similarly, benzocain gluconyl-acetyl salicylate may be written as:

CIHA. C 0 O .C 2H5 N-JELQ HLOKCHlC 0).c 0 OH 0 0 (HO cinnamon and procaine gluconyl borate may be written as:

CQH4.C O O.C2HAN(C2H5)2 N-Htrna or or 4H3 0a.

0 0 (HC OH)4.CH2OH In addition to the above salts of. the aldonyl anesthetic compounds, I have also prepared the citric, tartaric, picric and cinnamic acid salts of procain and benzocain gluconyl compounds, utilizing the method of direct union in a suitable solvent, such as water, acetone or alcohol, as the case may be.

The compounds of the present invention and their salts are characterized by the increased anesthetic potency, due to the increased molecular weight; lesser toxicity because of the introduction into the molecule of the aldonyl groupings; and increased combining power with acid substances because of the presence of numerous hydroxyl' groupings in the newly formed compounds, which in consequence increase their solubility in water.

This completes the description of the products and processes of the present invention. And it is to'beunderstood that I do not wish to limit myself to the specific products and processes hereinabove described, as, obviously, many varia-' tions of the same may be made, without theuse. of the inventive faculties and within the spirit and scope of the present invention and the claims appended hereto. v

What I claim as my invention is:

1. An aldo-nyl compound of an anesthetic ester of an amino aromatic acid of the single benzene nucleus series from the group of benzoic and cinnlamic acid having the general structural formula of wherein R is an ester of an amino aromatic acid of the single benzene nucleus series from the group of benzoic and cinnamic acid, R is a member of the group consisting of hydrogen and a her from the group consisting of hydrogen and a hydrogen substituting madicle, and R." is a lactone grouping fmomthe group consisting of gluconic acid lactone, galacto-nic acid lactone, mannomc acid iactone, xylonic acid lactone and aglucoheptonic acid lactone.

3. An aldonyl compound of an anesthetic alkyl ester of an amino aromatic acid of the single benzene nucleus series having the general structural formula. of

coon

in which R is an alkyl radicle derived from a lower alkyl alcohol, R is a member of the group consisting of hydrogen and a hydrogen substituting radicle, and R" is an aldonyl grouping derived from an al-donic acid l-actone.

4. An aldonylcompound of an anesthetic alkamine ester of an amino-aromatic acid of the single benzene nucleus series having the general structural formula of COO.R

in which Ris an :alkamine radi-cle derived from a lower ialkamine alcohol, R is a member of the group consisting of hydrogen and a hydrogen substituting rradicle, and R" is an aldonyl grouping derived from an aldcnic acid lactone.

5. An al-donyl compound of an'anesthetic aryl ester of an amino aromatic acid of the single ben zenenucleus series, having the general' -s tructural formula of R -N R" in which R is an aryl radicl derived from an a'ryl alcohol of the benzene series, R is a member of the group consisting of hydrogen and a hydrogen substituting radicle, and R is an aldonyl grouping derived fmom an aldon-ic acid lactone.

6. An aldony-l compound of an anesthetic ester of an amino aromatic acid of the single benzene nucleus series formed by the condensation of the amino aromatic acid ester with a 'lactone of an aldonic acid.

7. An'aldonyl compound of an anesthetic ester COO.R

in which R is a madicle derived from an alcohol of the group consisting of lower alkyl and lower alkamine alcohols and aryl alcohols of the benzene series, R is a member of the group consisting of hydrogen and a hydrogen substituting radiole, and R" is a gluconyl grouping derived fmom gluconic acid lactone.

10. An aldonyl compound of benzocaine formed by the condensation of benzocaine with the lactone of an aldonicacid.

1 11. A gluconyl compound of benzocaine formed by the condensation of benzocaine witha lactone of gluconic acid.

12. The method for preparing an aldonyl compound of an anesthetic ester of an amino aromatic acid [of the single benzene nucleus series which comprises the steps of dissolving a definite quantity of the anesthetic ester a solvent that will not react with the components, separately dissolving a substantially equimolecular quantity of the lactone of the desired aldonic acid in water, mixing the two solutions upon bringing them togethea', subjecting the mixture to steam pressure of substantially between 22 to 25 pounds until reaction is wmpleted, and then removing the solvents;

13. The method for preparing the aldonyl compounds of an anesthetic ester of an amino-aromatic acid of the single benzene nucleus series which comprises the steps of dissolving a definite quantity of the anesthetic ester a volume of a volatile solvent suflicient to form a solution of less than fifty percent (50%) concentration, said solvent to be of a type that will not react with the components, separately dissolving an equimol'eoular weight of the laotone of an aldonic acid in water, mixing the two solutions, subjecting the mixture to a, steam pressure of substantially 22 to 25 pounds until reaction is completed, and then memoving the solvents.

14. The method for preparing the aldonyl oompound. of an anesthetic ester of an amino aromatic acid. .of the single benzene nucleus series which comprises the steps of dissolving 'a. defimte quantity 'of th anesthetic ester in a solvent that will not react with the components, in a. sumcienlt quantity to f om a solution of less than fifty percent (50%) concentration, separately dissolving a. substantially equimolecular weight of the ltaictone of rthe fiesired aldonic acid in water, mixing the two solutions upon bringing them [together, subjecting the mixture to a steam pressure of substantially 22 to 2 5 pounds and then removing the solvents.

DAVID C'IZJRTIS. 

